What is LP Siding?

First, let me say that there has been a lot written about LP siding issues, and that we are by no means the experts on the subject.  The internet has an abundance of history and background on this subject.  Our intent is just to provide some insight in the event you are a homeowner that may have LP siding, or a buyer leery of potential siding replacement costs.

LP is Louisiana-Pacific Corporation, a building materials manufacturer.  LP pioneered the U.S. production of Oriented Strand Board panels – more commonly known as “OSB”.  You’ve most likely seen it before.

In the 1970s, LP needed a new product as Southern Pine and Douglas Fir timber were in short supply. The answer was faster growing and less expensive Cottonwood and Aspen. By the late 1970s, the production of OSB began by slicing logs into wafers, adding resin and pressing into sheets called Waferwood. Waferwood would later become Inner-Seal, a new product that took the industry by storm. It was a cheaper alternative and stronger than plywood sheathing and existing sub-flooring products.  LP called this new Inner-Seal product, “the smart man’s plywood”.

What is the problem here?

The Inner-Seal product, manufactured from the early 1990s through about November 1996, carried a 25-year warranty. Claims quickly began surrounding the quality of the panels, and claimants stated that the panels were disintegrating, growing mold and discoloring.

It was found that the panels actually absorb moisture at the bottom of the panel, unless extremely well insulated from the elements through continued and regular painting and sealant between panels.  Without the high level of preventative maintenance (that consumers generally weren’t aware of) the water seeps into this highly absorbent material, expands and damages the integrity of the panel. The moisture continues to seep up behind the panels, eventually spreading mold in the underlying vapor barriers, but mostly affecting areas around windows and framing, leading to rot in wood that may not be detected until too late.

Class action lawsuits ensued, and there was a period of time where homeowners could file claims. And most claims were regarding the simulated cedar Inner-Seal exterior siding – what we refer to as “LP Siding”.

That class action lawsuit claim period has now past.  And since 1997, LP re-engineered their product and now markets LPSmartSide, selling over 3 billion square feet with no warranty claims for fungal decay to date.

How do I know if I have LP siding?

After touring a few homes with the LP siding in question, it is fairly easy to tell if you have it.

Here are some telltale signs:

Homes built in the Northwest from 1990-1996 with horizontal plank siding are more likely to have the LP siding in question.

LP siding has a distinct look of cedar, as compared to the common replacement,
HardiePlank Lap Siding, from James Hardie Company.See the examples here. Note that the LP siding on the top has a rougher cedar-like look to it, while the HardiePlank below has a smoother look to it.HardiePlank Lap Siding Example

LP siding expands in moisture, and mostly on the weather-side of homes, so you may be able to see the expansion if affected. In the Northwest, look to the South or Southeast side of the home for the most evident damage if any.

 

 

Here are a few examples where moisture has caused expansion in the siding:
LP Siding Example 3
LP Siding Example 5

 

 

 

 

 

 

If you are buying a home, your inspector will determine if it has any siding issues (and we wouldn’t let you buy a home without having an inspection!)

What do I do if I have LP siding?

First, if you plan on selling your home, consult with us. We can help you determine – among many things – if you need to have your siding replaced or even just inspected by a licensed contractor specializing in LP Siding issues. We have contractor contacts to help you.

If the LP siding was cared for extremely well, and continues to be maintained, there may only be minimal replacement need at the current time. Don’t assume it all has to be replaced, but let a licensed contractor determine that!

If you do encounter siding issues as a buyer or seller, in some cases, it can be addressed as part of the sale of the home.

In Closing…

Get expert advice. If you are thinking of selling your home, contact us and let us take a look at your home.  We can help you determine the best repairs and improvements – if any – needed to get you the most out of your home.  And if you’re a buyer, we’re already on the lookout for you!

Comments are closed.